1. Technical Field
The present invention relates to an arrangement for a weaving machine which operates with one or more warp thread tracks which lead from warp thread magazines towards a transverse shuttle race. At the latter a fell of the cloth is established by means of one or more shuttles, and each weft thread or weft threads can be drawn in with the reed during ongoing weaving.
2. Description of Related Art
In this type of weaving machine it is previously known to let the warp thread track run across one or more whip rolls and one or more auxiliary back beams. It is also known to design each whip roll and auxiliary back beam so as to be rotatable by the warp threads, which affords advantages from the point of view of thread tension. By virtue of the rotation of the whip roll and the auxiliary back beam it is easy, in contrast to the case with fixed, non-rotating whip rolls and auxiliary back beams, to control the feed of the warp threads from the warp beam or warp magazine concerned, so that the thread tension in the warp threads is maintained essentially constant during the entire weaving process.
The known apparatuses are disadvantages when used to weave high-quality cloths or cloths of material which is sensitive from the point of view of weaving. The rotation of each whip roll and/or auxiliary back beam results in the resistance of the warp thread, as a result of the drawing-in force of the reed towards the fell of the cloth during each weaving pick, being effected by the warp beam/magazine. The warp thread track between the warp beam and the fell of the cloth is comparatively long, and the arrangement, together with the fact that the warp threads themselves have a certain stretchability/elasticity, results in a flexibility/resilience of the warp threads when the reed is pressed against the fell of the cloth and the return of the fell of the cloth to a position determined by the elasticity of the warp thread system, as soon as the pressing force of the reed ceases, etc.
The above spring negatively effect resulting from the elasticity the structure of the cloth/fabric.